Investigating the syphons

Not the GWR milk/parcels/newspaper carrying items of non-passenger coaching stock. (There is one of those on the railway, Siphon G 2983, details on this page of the Vintage Carriages Trust website – http://www.ws.rhrp.org.uk/ws/WagonInfo.asp?Ref=168). No, we are talking of syphons, the wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the fall of the liquid as it flows down the tube under the pull of gravity, then discharging at a level lower than the surface of the reservoir from which it came. We use the spelling with a Y, the alternative spelling with an I reveals its derivation from Ancient Greek σίφων (síphōn) meaning 'pipe’ or ‘tube'. We have 5 syphons which run underneath the railway track; four are small(ish) diameter so we classify these as cross drains, one is larger so is a culvert. Two of our syphons are at Bishops Cleeve, either side of Two Hedges Road; both were subject to alterations around 30 years ago as part of the reopening back to Cheltenham Racecourse. Hence high time to attend to the effects of time and weather since then.

Thursday 27^th February

Nine of the team attending on our last working day of the (metrological) Winter. Six of the team went syphon investigating at Bishops Cleeve, the other three attending to Working Lane haul road.

First was a delivery of spent ballast to Bryan at Gotherington station to use for driveway repairs. Jonathan loaded this with the telehandler at Winchcombe onto the tipper Transit; then Dave and Peter delivered it to Gotherington.

Spent ballast delivered to Gotherington Station. [Photo by Dave]

The three of them then proceeded to the bottom of the haul road at Working Lane. Jonathan used the telehandler to clear a path through the pile of debris to enable some of the water that is collecting there to drain away into the boundary ditch.

Clearing a drainage channel through the debris at the bottom of the haul road. [Photo by Dave]

Meanwhile Dave and Peter loaded some good reclaimed red bricks for transport back to Winchcombe. These had been the only materials moved to Working Lane when the intention was to use that area for storing drainage items. The stack of bricks were surrounded by old pallets, which had become a ‘bug hotel’. So these were taken up to the top of the haul road to construct a new ‘bug hotel’ by the boundary hedge near to the stack of cut logs. Together these will provide spaces for insects and small mammals.

Peter loads the recovered red bricks. [Photo by Dave]

The new 'bug hotel' under construction at the top of the haul road. [Photo by Dave]

 

Finally at Working Lane, Dave and Peter cleared out the grill on the down stream exit of culvert 24C under the railway boundary; they also checked the up side entry as there was more than the usual amount of debris in the channel.

Roger, Nigel, Polly, Ian, Martin and Andrew were the six headed for Bishops Cleeve. First task was at syphon cross drain 39B. The down (Cotswold) side inlet, originally an L shaped headwall, had in the past been extended into a chamber covered with concrete sleepers. Some of the chamber sides are now displaced, so will need rebuilding. Roger, Ian, Martin and Andrew drew up the plan for this; it will include fitting a proper blue mesh lid to replace the concrete sleepers. Meanwhile Nigel and Polly renewed the mortar flaunching around the metal manhole lid which takes the inlet from the run off on footbridge 39Z. (The footbridge is on the low mileage side of the main Two Hedges Road bridge which is number 40, hence the 39 number).

Ian (left) and Roger remove the concrete sleepers to reveal the syphon inlet chamber of 39B.

Three displaced coping bricks on the original headwall of 39B inlet.

Polly completes the new flaunching around the metal manhole of 39B road run off inlet.

Then over to the up (Malvern) side. Here the original syphon exit is in a pit partly under a gate in the security fence. At some time in the past, probably when the houses on Jesson Road and Two Hedges Road were built, the outlet had been extended in concrete pipes to outside railway land. Excavating this pit revealed a gap in the first join of the concrete pipes; we quickly sealed this with some more mortar. Again we established the rebuild plans, this time we will use concrete lids because of the clearance needed under the fence.

Currently the cover of the 39B exit pit is this old section of security fence. Loose section of brick just visible underneath.

On the high mileage side of Two Hedges Bridge is syphon cross drain 40A. Here the up side outlet is way outside of railway land on the other side of Pargets Road. (The water course eventually ends up in the Dean Brook.)  There is a metal centre washout lid in the up side cess – here we will construct a small wall around it to prevent vegetation encroachment and thus keeping it visible to clearance teams. On the down side, the actual syphon inlet is now buried. More concrete sleepers cover part of a U shaped brick invert which leads to this. The big puzzle is a circular depression in the invert. After prodding this with a crowbar and a long handled spade, we think this is just a slit trap. As the flow through the syphon appears to be good with no leakage into the cess drains; and the U shaped invert is in reasonable condition, the only item for our ‘to do’ list here is fitting a better lid to replace the concrete sleepers. But that is certainly nowhere near the top of the priority list.

Looking towards the inlet of 40A underneath the track at the top of the cutting. Part of the circular silt trap visible in foreground. [Photo by Ian]

Close up of the circular silt trap in the base of 40A inlet.

Looking down the U shaped invert of 40A towards the syphon entry. [Photo by Ian]

Martin, Ian and Roger take a breather before replacing the last of the concrete sleepers on the 40A inlet.

 

The next drainage channel south is definitely on our priority list! Just before milepost 17½, a stream which originates on Cleeve Hill and gathers spring water on its way down, enters under the down side boundary at the top of the cutting. There is intermediately a 90 degree bend; the water then heading south. Over topping of the crest ditch here has been a long running problem. A few years ago, the team aided by one of our contractors added a French drain with two perforated twinwall pipes in it to take any excess water down to a new chamber in the down side cess. The 90 degree bend was improved with a circular manhole and part of the crest ditch was piped. (See here.) Unfortunately our contractors did not complete the piping of the crest ditch as they were redeployed to a more critical repair.

The down side cess chamber which gets the overflow from the Cleeve Hill stream. Water dribbling out of the two twinwall pipes and oozing from the cutting side through the concrete ring slots.

Checking the flow in the 90 degree bend manhole.

We rodded the two perforated twinwall pipes from the down side cess chamber – this proved that they are not blocked with silt and showed where they start in the crest ditch. We also removed silt and other debris from around the cess chamber and the lower part of the French drain. We also examined the circular manhole , this confirmed that all of the water entering does indeed make the 90 degree turn to exit into the crest pipe. It looks like it is the first join in the crest pipe that is leaking. So next task is to dig out around that.

The pointed end of the drain rods emerges from one of the twinwall pipes into the crest ditch.

A lot neater with the silt and debris removed from the bottom of the French drain and the down side cess chamber.

 

All this water does eventually reach cross drain 40B. Nigel and Polly knocked off a couple of minor repair jobs for that, some repointing around the barrel on the outlet of the main structure and to the rear of the small headwall where the down side cess drain enters the toe ditch.

Brickwork repair team, Polly (l) and Nigel, at 40B up side exit.

 

As ever when working at Bishops Cleeve, we cleared up quite an assortment of items that our neighbours have donated. Amongst the haul was almost a dozen assorted balls of various sizes; a twelve foot scaffold pole (which will be useful for safety rail construction) and a concrete bird bath.

Back at Winchcombe, we stacked the recovered bricks from Working Lane on a decent pallet. Finally our last task was to move our stock of milepost heads and materials for numerals from the old wooden workshop to the block built shed. The old wooden workshop and office are due to be demolished in April.

Wildlife report: Not a great deal of note to report. A friendly black cat paid a brief visit to us at Bishops Cleeve, a flock of finches was noted a bit further south, with gulls, wood pigeons, crows and blackbirds circling overhead. Spring’s imminent arrival was apparent with some new growth appearing on blackberry brambles; still plenty of snowdrops but all now past their best. Most daffodils we noted are still in bud, a noticeable exception being those in front of the entrance to Churchward House which are already in full bloom.